Mana basin

The false x-ray tetra, Hyphessobrycon simulatus, is a characid endemic to French Guiana, from the Maroni to the Oyapock/Oiapoque river basins. Uncommon in the trade, it was originally described in the genus Pseudopristella. It is told from Pristella maxillaris by a larger humeral spot and black in the anal fin limited to the first ray.

Hyphessobrycon borealis is a small characid from French Guiana, recorded from the Oyapock/Oiapoque to the Maroni river systems. It inhabits shallow marginal zones with little current, where it forms large schools. The largest recorded specimen measured 27.8 mm, and the species lacks a humeral spot but has an oval spot on the caudal peduncle.